I’d like to add: in order to have a 3D effect, you need to set the perspective on the parent of the element that gets the 3D transform. if not, there is no perspective, and the 3D effect is weird.
For example, if I exaggerate the rotation on your element, you can see what’s going wrong: no perspective, it turns flat:
If you select it parent element, and set the children perspective to 2000, you’ll see that the perspective is there now.
So set children perspective on .case-study-hero, the parent element of your brown square, and your interaction will seem more natural.